"OK, Google"

When you want to perform a search, find nearby locations, or get directions, just say, "OK, Google" to your G Watch and speak your query. As you can see in this screen, if it doesn't register, you can try again.

Voice command included too

Because it supports voice command, you can also record voice memos or
activate commands. Simply say, "OK, Google, set an alarm for 7 a.m.,"
and your watch's alarm will start blaring at the appropriate time the
following day.